{"id":"CVE-2026-53271","state":"PUBLISHED","title":"ksmbd: fix NULL-deref of opinfo->conn in oplock/lease break notifiers","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix NULL-deref of opinfo->conn in oplock/lease break notifiers\n\nsmb2_oplock_break_noti() and smb2_lease_break_noti() read opinfo->conn\ninto a local with neither READ_ONCE() nor a NULL check.  Both run from\noplock_break() after opinfo_get_list() has dropped ci->m_lock, so a\nconcurrent SMB2 LOGOFF (session_fd_check()) can set op->conn = NULL\nunder ci->m_lock within that window.  ksmbd_conn_r_count_inc(conn) then\nwrites through NULL at offset 0xc4 -- a remotely triggerable oops.\n\nGuard both reads the way compare_guid_key() already does: read\nopinfo->conn with READ_ONCE() and return early if it is NULL, before\nallocating the work struct so nothing leaks.  A NULL conn means the\nclient is gone and the break is moot, so return 0; oplock_break() treats\nthat as success and runs the normal teardown.","publishedAt":"2026-06-25T08:39:56.489Z","updatedAt":"2026-06-25T08:39:56.489Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"8df4bcdb0a4232192b2445256c39b787d58ef14d","status":"affected","lessThan":"945a86b21b40fb17183f5b27461baa6f03e2467f","versionType":"git"},{"version":"c8efcc786146a951091588e5fa7e3c754850cb3c","status":"affected","lessThan":"1ff58dcfcab434ebb51649da33774fbb8e1f7b67","versionType":"git"},{"version":"c8efcc786146a951091588e5fa7e3c754850cb3c","status":"affected","lessThan":"e735dbd489e3ea02be78dba991056fe1138be51e","versionType":"git"},{"version":"c8efcc786146a951091588e5fa7e3c754850cb3c","status":"affected","lessThan":"75e33deda658c1ab3a9336cbdb1436536f9b3660","versionType":"git"},{"version":"c8efcc786146a951091588e5fa7e3c754850cb3c","status":"affected","lessThan":"b003086d76968298f22e7cf62239833b5a3a06b1","versionType":"git"},{"version":"6.6.32","status":"affected","lessThan":"6.6.143","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/oplock.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.9","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.94","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.36","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.13","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/oplock.c"]}],"references":["https://git.kernel.org/stable/c/945a86b21b40fb17183f5b27461baa6f03e2467f","https://git.kernel.org/stable/c/1ff58dcfcab434ebb51649da33774fbb8e1f7b67","https://git.kernel.org/stable/c/e735dbd489e3ea02be78dba991056fe1138be51e","https://git.kernel.org/stable/c/75e33deda658c1ab3a9336cbdb1436536f9b3660","https://git.kernel.org/stable/c/b003086d76968298f22e7cf62239833b5a3a06b1"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53271.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53271","state":"PUBLISHED","datePublished":"2026-06-25T08:39:56.489Z","dateUpdated":"2026-06-25T08:39:56.489Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-06-09T07:44:35.395Z"},"containers":{"cna":{"title":"ksmbd: fix NULL-deref of opinfo->conn in oplock/lease break notifiers","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix NULL-deref of opinfo->conn in oplock/lease break notifiers\n\nsmb2_oplock_break_noti() and smb2_lease_break_noti() read opinfo->conn\ninto a local with neither READ_ONCE() nor a NULL check.  Both run from\noplock_break() after opinfo_get_list() has dropped ci->m_lock, so a\nconcurrent SMB2 LOGOFF (session_fd_check()) can set op->conn = NULL\nunder ci->m_lock within that window.  ksmbd_conn_r_count_inc(conn) then\nwrites through NULL at offset 0xc4 -- a remotely triggerable oops.\n\nGuard both reads the way compare_guid_key() already does: read\nopinfo->conn with READ_ONCE() and return early if it is NULL, before\nallocating the work struct so nothing leaks.  A NULL conn means the\nclient is gone and the break is moot, so return 0; oplock_break() treats\nthat as success and runs the normal teardown."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"8df4bcdb0a4232192b2445256c39b787d58ef14d","status":"affected","lessThan":"945a86b21b40fb17183f5b27461baa6f03e2467f","versionType":"git"},{"version":"c8efcc786146a951091588e5fa7e3c754850cb3c","status":"affected","lessThan":"1ff58dcfcab434ebb51649da33774fbb8e1f7b67","versionType":"git"},{"version":"c8efcc786146a951091588e5fa7e3c754850cb3c","status":"affected","lessThan":"e735dbd489e3ea02be78dba991056fe1138be51e","versionType":"git"},{"version":"c8efcc786146a951091588e5fa7e3c754850cb3c","status":"affected","lessThan":"75e33deda658c1ab3a9336cbdb1436536f9b3660","versionType":"git"},{"version":"c8efcc786146a951091588e5fa7e3c754850cb3c","status":"affected","lessThan":"b003086d76968298f22e7cf62239833b5a3a06b1","versionType":"git"},{"version":"6.6.32","status":"affected","lessThan":"6.6.143","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/oplock.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.9","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.94","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.36","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.13","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/oplock.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/945a86b21b40fb17183f5b27461baa6f03e2467f"},{"url":"https://git.kernel.org/stable/c/1ff58dcfcab434ebb51649da33774fbb8e1f7b67"},{"url":"https://git.kernel.org/stable/c/e735dbd489e3ea02be78dba991056fe1138be51e"},{"url":"https://git.kernel.org/stable/c/75e33deda658c1ab3a9336cbdb1436536f9b3660"},{"url":"https://git.kernel.org/stable/c/b003086d76968298f22e7cf62239833b5a3a06b1"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-06-25T08:39:56.489Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.32","versionEndExcluding":"6.6.143"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.12.94"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.18.36"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"7.0.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}